GULF OF MEXICO 



225 



and other marine animals. There is every reason 

 to bcHevp that many species of dinoflagcllates 

 elaborate an extremely potent toxin either nor- 

 mally or under the conditions of population 

 crowding. The two blooms cited above were 

 associated with serious "fish kills" and death of 

 much of the marine life in the area. 



The presence of even normal numbers of dino- 

 flagellates in the water may cause shellfish to 

 become unfit for human consumption. Thus, reg- 

 ularly during the summer months the California 

 sea mussel (Mytihis californianus) is likely to be 

 lethal to humans when Gonyaulax catenella 

 Whedon & Kofoid is abundant in the coastal 

 water (Sommer et al., 1937), and the clams in 

 certain areas of the Bay of Fundy are regularly 

 toxic when Gonyaulax tamarensis Lebour occurs 

 in the plankton (Medcof et al., 1947). Paralytic 

 shellfish poisoning caused by eating such toxic 

 shellfish has not been reported from the Gulf of 

 Mexico. Connell and Cross (1950) found a dino- 

 flagellate resembling Gonyaulax catenella associ- 

 ated with the death of fish in Offatts Bayou, an 

 inlet of Galveston Bay, in 1949. Unfortunately, 

 no specific identification of this organism was 

 made. There is also strong evidence that the 

 fish kills which regularly occur in Offatts Bayou 

 are generally caused by the production of hydrogen 

 sulfide or to suffocation due to stagnant conditions 

 at the inner end of the inlet (Gunter 1942, 1951) 

 rather than by a dinoflagellate bloom. 



Toxic red water such as occurs regularly in the 

 pearl oyster beds in Japan (Mitsukuri 1904) could 

 be disastrous to the vast oyster industry in the 

 Gulf, but apparently the Gulf oysters have been 

 spared any such visitation so far. 



Reports of red water on Campeche Banks, off 

 Yucatdn, are made occasionally by fishermen in 

 that area, but to date it has not been possible to 

 ascertain the causative agent. It is quite possible 

 that a dinoflagellate is involved. 



One of the great difficulties in dinoflagellate 

 research is the fragility of the naked forms. 

 Many of these are almost impossible to preserve 

 but must be studied alive under the microscope. 

 This feature might not be serious if the organisms 

 were easily cultured, but they are notoriously 

 difficult to grow in the laboratory. The classical 

 monograph of the unarmored dinoflagcllates by 

 Kofoid and Swezy (1921) was based largely on 

 examination of living specimens which regularly 



dissolved before the eyes of the workers as they 

 stutiied them. The Florida red tide was caused 

 by such a naked form, G. hrevii, which does not 

 preserve in formalin. Special fixatives such as 

 Bouin's solution and Schaudinn's solution do pre- 

 serve some of these species but not without 

 distortion. 



However, a rich fauna of unarmored forms is 

 not normally present inshore at Sarasota, Florida, 

 where the workers of the Fish and Wildlife Service 

 laboratory in their search for G. hrevis have exam- 

 ined living material for 2 years and failed to 

 reveal any G. hrevis. They foimd only three other 

 species of unarmored dinoflagcllates. More work 

 in other areas must be conducted before this 

 problem can be solved. 



The difficulty in making specific identification 

 of dinoflagellates has lead to a paucity of records 

 of these interesting and important organisms. 

 Painstaking microscopic work on the part of a 

 specialist is necessary for the differentiation of 

 many species, even of the thecate forms which 

 preserve well. 



In these species, an analysis of the plate pattern 

 is necessary for identification. Few general plank- 

 tologists have either the time or traming to pursue 

 this kind of work which involves difficult micro- 

 orientation and dissection. Concentrated study 

 by a number of specialists for a considerable period 

 of time will be necessary before the dinoflagellate 

 plankton of the Gulf will be adequately revealed 

 to science. 



Since most of the pelagic tropical species of 

 dinoflagellates are worldwide in distribution, 

 published works for other areas can be used for a 

 study of the Gulf fauna. The most important of 

 these are listed in the bibliography. Lebour's 

 (1925) work is designed for northern seas but 

 includes many tropical species. It is a very useful 

 treatise, especially for a beginner who needs 

 orientation. Kofoid and Swezy 's (1921) mono- 

 graph is a classic on the naked forms but must be 

 augmented by later papers. Kofoid and Skogs- 

 berg's (1928) Dinophysoidae is another classic 

 and covers that group in a comprehensive manner. 

 The Heterodiniidae has been monographed by 

 Kofoid and Adamson (1933). Most of the 

 Peridiniidae are in need of monographic treatment. 

 It is very difl[icult to identify the smaller species 

 with present literature. For the Ceratia Jor- 

 gensen's (1911) monograph and Graham and 



